ERPs associated with the stop task. Grand-mean average response-locked ERPs at Fz, Cz and Pz for stop-errors and correctly responded stimuli.

<p>The negative-going deflection following a stop error is the ERN. Note the increased amplitude of this wave in the MS patients (solid line) as compared to the healthy controls group (dotted line). The grand-averages have been band-pass filtered (2–8 Hz) for display purposes. The topographical map shows the peak activity of the ERN expressed as the difference wave between error—correct responses. Relative scaling was used. Minimum and maximum values: -5/0 μV.